Author Topic: Distributor makeover.  (Read 1345 times)

0 Members and 1 Guest are viewing this topic.

Offline Brooklands

  • Bronze Member
  • **
  • Posts: 1153
Distributor makeover.
« on: December 20, 2012, 08:56:54 pm »
This topic relates to distibutor engined bikes and concentrates on a rebuild of the base plate- in the case a '48 C11, which ticked over quite well, but with the odd miss but felt hesitant at low to mid revs, up to underpowered at higher engine speeds. It had had new shaft bushes fitted by Draganfly, and the bob weights & springs all looked OK, points gap OK., condenser old, mixture of odd fittings keeping it all together - typical of 'home' maintenance & dropped screws & washers and representative of an 'as found' bike.
First tests were to run the bike in the dark, watching the points. The odd hiccup at tickover matched an occasional fat spark at the points. Then tested HT side - coil lead a bit loose at coil, fitted my home-made spark tester in series and ran the engine and watched spark - spark wandered around the electrode, was yellowish, and the odd miss could be seen.   
So, closer inspection of the base plate. That revealed an over-long screw that had been eaten by the bob-weights, worn fibre points block, and, more importantly, the pin that the points sit on was also badly worn. So fitting a new set of points would be a waste of money without sorting the pin first . Fortunately the owner had a spare base plate with a perfect pin, but new plates are available for around £20. The same base plate also had a great set of fixing screws too. So just a new condenser and points to source - at around £15 for the two. To be continued.....
Norfolk 'n good!

Offline Brooklands

  • Bronze Member
  • **
  • Posts: 1153
Re: Distributor makeover.
« Reply #1 on: December 20, 2012, 09:04:58 pm »
Next job was to assemble all of the parts - there's around 25 bits & pieces that go in there! First job is to clean up the ends of the metal band that goes from the condenser to the points and fit the condenser to the band. Then, if its there, drop in the small spacer that goes under the condenser bracket, but leave the bracket slack. Fit the band into the distributor & tighten the outer terminal nut onto its washer, the move the band along the condenser to align the screw holes. Fit the screw & washers, turn over and check the screw doesn't poke through too far. Put the bottom points plate in place, along with its fibre washer, and lubricate to pin with a drop of engine oil.
Norfolk 'n good!

Offline Brooklands

  • Bronze Member
  • **
  • Posts: 1153
Re: Distributor makeover.
« Reply #2 on: December 20, 2012, 09:11:39 pm »
Previous picture shows a pointer - the small brass top-hat spacer needs to be fitted, along with the moving point, carefully putting the spring loop over the stud, the fitting the second top hat, washer and nut. Fit the 2 points baseplate screws & just nip up. Copa slip the 2 screws that go into the distributor body to prevent them seizing. Apply a small amount of oil to the bob weight assembly, and, if it's there, a few drops to the shaft lubricator, just under the main distributor body. Make sure you have a good, soldered & insulated low tension lead terminal.
Norfolk 'n good!

Offline Brooklands

  • Bronze Member
  • **
  • Posts: 1153
Re: Distributor makeover.
« Reply #3 on: December 20, 2012, 09:27:36 pm »
Apply a small amount of grease to the cam, tighten the allen screw, having applied a drop of oil to the recess in the cam top.
Turn the base plate over and make sure that no screws project into the bob-weight area. Hold the points cam open with your thumb and put the base plate onto the distributor and fit the 2 screws that keep it there. With the plug out, easy the engine over to the point where the points heel is on the high point of the cam, and set the points to 12 thou, by just nipping the points screws and using the blade of a screwdriver to lever them open or closed. It may take more than one go, as finally tightening the screws usually moves the settings a little. Connect the low tension lead.
Check the spark plu lead by removing it from the coil and from the plug cap - if in doubt, replace it - a foot of cable is as cheap as chips. This one had been soldered at the coil end - hence it coming loose. The split washer acts as a shakeproof washer, and the wiresshould just the splayed evenly.
With the plug lead back on the coil, feed the lead through to the right hand side of the engine, fit the (cleaned) plug to the lead and rest the plug body on the exhaust. With the ignition on, turn the engine over and you should hear a strong 'click' from the plug and see a good blue spark at the plug terminal when the points open. If you see a fat spark at the points, backtrack and make sure all is as it should be, or replace the condenser.
The effect was dramatic - easy starting,smooth running, crisp exhaust note and a big step up in engine power - £15 well spent!
Joe
PS, cosmetically the flat part pof the distributor body should be positioned differently, but that's for another day.
Norfolk 'n good!

Offline IanK

  • Full Member
  • *
  • Posts: 20
  • Country: gb
Re: Distributor makeover.
« Reply #4 on: January 01, 2013, 10:13:04 pm »
Wow

Top class pics and instructions, I've got some way to go!

Ian
1953 C10

Warrington, Cheshire

Offline ricky77

  • Full Member
  • *
  • Posts: 96
  • Country: it
  • Location: massa tuscany
Re: Distributor makeover.
« Reply #5 on: February 19, 2019, 03:22:23 pm »
wich is the best site to buy repalcement screw and bolt for distributor base plate?is avaiable a kit for it? i found a new base plate bakelite as this one
regards ricky